Unit for cutting materials by heat



July 21, 1953 R. W. FEGAN UNIT FOR CUTTING MATERIALS BY HEAT Filed June 21, 1950 mmvroa.

; k ROBERT W. FEGAN i ATTORNEY Patented July 21, 1953 Robert W. Fegan, Kenmore, N. Y., assignor' to George B. Hart, Inc., Rochester, N. Y., a corporation of New York Application June 21, 1950, Serial No. 1 69399 1 Claim. (01.219 49) v 1 r My invention relates to a unit for cutting materials by heat, particularly such materials as polystyrene products, thermoplastics and other materials which may be readily out upon being contacted by a high temperature resistance wire.

An object of my invention is to provide a cutting unit particularly suitable for cutting styrene products, thermoplastics andother materials by-a current carrying high resistance'wire which is inexpensive to manufacture and convenient to use.

A further object of my invention is to provide 4 a resistance wire so mounted with relation to a work surface that polystyrene products, thermoplastics and other materials may be conveniently cut for the purpose of making decorative designs for use in displays by fiorists, in funeral work, in trimming store windows and for other decorative purposes. I

My invention further contemplates a highresistance wire adapted easily and conveniently to cut polystyrene products, thermoplastics and other materials when heated by an electric current, the wire being so arranged with respect to a platform to one end of which the resistance wire is anchored and with respect to a mounting member to which the other end of the resistance wire is anchored that when the wire expands or lengthens due to heat theincreased length is automatically taken up so as to maintain the wire taut and facilitate the cutting operation.

Other objects and advantages of my invention will be particularly set forth in the claim and will be apparent from the following description, when taken in connection with the accompanying drawings, in which:

Fig. 1 is a perspective view of the cutting unit of my invention;

Fig. 2 is a sectional view taken substantially on the line 2--2 of Fig. 1 in the direction indicated' by the arrows;

Fig. 3 is a view of the under side of the box or platform which houses parts of the unit; and

Fig. 4 is a sectional view taken substantially on the line l& of Fig. 3 in the direction indicated by the arrows. V

It has been customary practice in decorative out designs, for example, blockletters, maybe made of polystyrene or other materials and such decorative designs have many other uses in floral 2 and funeral work.

Heretofore it has been the practice to out such polystyrene products, thermoplastics or other materials with a metal saw'which is difiicult to handle, doesJnot produce a smooth out and is difficult to maintain and control along a desired line of cut. I have found-that suchmaterials may be more easily cut and a smooth'cut ap- I pearance produced when the cut is made by a current carrying high resistance wire.

I The cutting unit of my invention may comprise a box or rectangular shaped structure, generally indicatedby the numeral H, which has a work receiving platform or top surface 12 and side and end walls I 3. view of the under side of the box I l, as indicated at 14, the unit is connected by a suitable electric cord to a wall socket in the usual manner. lead I6 from the source of current passes to a transformer, diagrammatically illustrated at I8, adapted to step down the current from, let us say, volts to 9 /2 volts. From the transformer 18, the current flows through a wire l9 to a terminal 2|.

As shown most clearly in Fig. 4, the terminal 2! includes a threaded conducting element 22 which extends through an aperture formed in a bracket 23 secured in any suitable manner beneath the top wall of the box ll. Suitable nuts 24 are provided for holding the lead I9 in place and the threaded member '22 is insulated from the bracket 23 by means of insulation members 26. A conducting washer 21 is carried by the threaded member 22 and a resistance wire 28 is wound around the threaded member 22 and clamped in position by a thumb nut 29.

The resistance wire 28 may be a nickel chrome alloy which is highly resistant to current flow therethrough and does not readily oxidize. The

28 may be wound around the threaded member work such as might be used by fiorists or funeral directors or in the trimming of store windows to make cut-outs of polystyrene products, I thermoplastics and other materials for the purpose of producing decorative designs. For example, in the trimming of store windows, it is sometimes desirable to make cut-out designs for use in connection with snow scenes. Such cut- Referring now to Fig. 3 which is a through an opening formed in the platform I2 and is rigidly secured by welding 31 to a support 38. Preferably the box H is a conductor and is connected as shown at 39 to a wire 41 which connects with the transformer as shown at 42. A switch 43 isconnected in the circuit so that upon opening and closing the same, current mayfiow as above described through the resistance Wire 28. The box of the cutting unit may be grounded as indicated at 45.

One fact of importance should be particularly noted. The resistance wire 28 tends to expand or lengthen when heated. The amount of"'expansion may be as much as %"in-a 12" length of wire. the wire should be maintained taut; otherwise it is difiicult to obtain a clean or. sharply defined cutting of the material. This is accomplished In order to obtain eflicient-qcutting,

in my invention by anchoring the wireaatxthe as to place the wire under tension. Thegoose- .neck36 thus has .a slight resiliencyfltending to cause .its outer-end or its point of attachment to the resistance wire 28-to move awayv from the -platform and thus automatically take up for any expansion in theresistance Wire asit isheated;

I have found the cuttingunit above described extremely useful in cutting such .materials as polystyrene products, thermoplastics and other materials which may be cutby heat. Theprod- .uctto be cut .to form, for example,'block letters or other designs, may easily be .moved over the platform withurelation'to the cutting wireand accurate control of the design to-be out can be obtained .by. a reasonably skillful worker.

While I have shown and describedithe preated that various changes and modificationsmay "ferredformof my invention, it will beapprecibe made, particularly in the form and relation of parts, without departing from the spirit of 7 my invention as set forth in the appended claim.

I claim: Apparatus for cutting materials comprising, in combination, a grounded box-like frame having a planar top surface upon which the ma- "terials'to bexcut are placed, said top surface having an opening toward the .front thereof, a gooseneck shaped conducting member carried by and in conducting relation with the platform adjacent the rear thereof and extending connecteditoztheend of said member, a terminal ward through said opening and being connected to said lterminal, said top surface afiording a planar area over which the articles to be cut ..may be moved in putting relation to said wire whichplanar'areavis-normal to said wire and unobstructedcexcept for the lower end ofsaid ggooseneck, and .means 7 including 'aswitch and a transformer located below said planar surface -for completing 1 the -..circuit through the resistance wire, said gooseneck'shaped member being sufficiently resilient -thatthe end of the member to which'the wire is attached tendsto move away from the terminal beneath the .top 1 surface to maintain the wire taut when it lengthensdue-to 

